1. Field of the Invention
The present invention relates to a novel compound, 2,3-dihydro-2,3,5-trimethyl-4H-pyran-4-one derivative, and a sex attractant for drugstore beetles. 2. Description of the Prior Art
Drugstore beetles (Stegobium paniceum Linne) are distributed worldwide and eat various substances including books and fibers and foodstuffs such as feeds, breads, or biscuits. Drugstore beetles also prefer herbs including medicinal carrots from which their name is derived, and are pests for stuffs stored in drug or food factories. Such indoor insects are closely associated with our daily life. For this reason, many safety measures must be taken in pest control of these worms and many pest control methods or drugs used for other types of insect cannot often be used. For example, in a specific type of warehouse, a fumigant having a strong toxicity such as hydrogen phosphide or methyl bromide is used as an insecticide for drugstore beetles. However, for the same purpose, only a DDVP drug can be used in factor working sites or warehouses in which people are expected to be exposed to such a drug frequently. However, the DDVP drug i.e., dimethyl 2,2-dichlorovinyl phosphate, does not have residual and permeating effects; it can kill adult drugstore beetles in an area in which they are easily exposed to the drug but it cannot kill adult drugstore beetles, or their eggs, larvae or pupas in concealed corners or the like. Thus, the DDVP requires frequent applicaton. Even if adult drugstore beetles are temporarily killed to a low population, emergence of remaining pupas may result in recovery of the original adult worm population within a short period of time. This presents a problem of frequent application of an insecticide and may be bad for health.
Many studies are recently made for attraction pest control using an insect sex pheromone or for pest control by disturbing communication between different sexes. In general, the mating behavior of insects is controlled by a very small amount of a scent-emitting substance secreted by insects themselves (normally female insects). An adult female insect emits a volatile material into the air, and an adult male insect flies or walks to the female insect emitting the volatile material. The male insect finds the female insect and becomes sexually excited so that the two insects engage in copulatory behavior. The scent-emitting substance from an adult female insect is generally called a sex pheromone or a sex attractant and is an important substance which controls the mating behavior of insects. Therefore, it is possible to attract and exterminate male insects at a selected location or to disturb normal mating behavior of adult male insects, thereby performing pest control. Further, when pests are attracted and exterminated using a sex pheromone and their occurrence is determined, need and timing for application of an insecticide can be determined and an insecticide will not be wasted.